Burglar-alarm.



1. W. SMITH.

BURGLAR ALARM.

AEPLIcATmN min AuG.20.-1915.

.zafra 'r onirica.

JAMES W. SMITH, OF BROOKLYN, NEW YORK.A

BURGLAR-ALARM.

Specification of Letters Patent.

Patented Nov. 14, 1916.

Application led August 20, 1915. Serial No. 46,569.

To all whom t may concern Beit known that I, JAMES W. SMITH, a citizen of the United States, lresiding at Brooklyn, in the county of Kings, State of New York, have invented certain new and useful Improvements in Burglar-Alarms; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as lwill enable others skilled in the art to which it appertains to make and use the same. Y

This invention relates to improvements in burglar alarms.

One object of the invention is to provide a novel and efficient device of this character which is used in connection with a door knob whereby an alarm will be sounded when the knob is turned in either direction.

Another object is to provide a device of this character of such construction that the alarm will ring continuously when setoff by opening the door.

Another object is to provide means for setting o the alarm should the door be opened in any manner without turning the knob.

Another object is to construct the Vdevice with a means whereby it can be made silent when the ringing of the bell is not desired.

Other objects and advantages will be apparent from the following description when taken in connection with the accompanying drawing.

In the drawing, Figure 1 is a front elevation of the device applied to a door knob, Fig. 2 is a vertical section on the line 2-2 of Fig. 1, Fig. 3 is a horizontal section on the line 3-3 of Fig. 2, and Fig. 4 is a diagrammatic view of the wiring.

Referring particularly to the accompanying'drawing, 10 represents a portion of a door and 11 the adjacent portion of the frame of the door. The knob spindle 12 is passed through the door and has secured Vthereon the shank 13, of a hollow metal knob 14 within which is mounted an electric vibrating bell 15. The knob is provided with a plurality of openings 16 to permit the sound'of the bell to escape. vSecured to the door and surrounding the knob shank is the escutcheon 17, said escutcheon carrying an integral outwardly extending circula-r flange 18 within which is secured a suitable ring or sleeve of insulation 19. Carried by the sleeve 19 are two metallic contact members 2O and 21 and carried by the knob shank is a. flexible metal strip 22, one end of which is constantly in engagement with the contact member 21. Connected with this strip is a wire 23 which is connected to the coils 24 of the bell 15. The other side of coil is connected to the contact point 25 of the armature 26, which is pivoted on the coil frame 27 and through the latter is grounded on the knob, as at 28.

Mounted on the door above the knob and forming a part of the escutcheon by means of the hollow portion 29,is a casing 30, in which is disposed anl electric battery cell 31, one element of which is in direct contact wiih the bottom of the casing, as shown at 2.

`The other or carbon element 33 projects at thetop which engages with a springpressed electric contactmember 34 carried by a screw' 35 disposed through the insulated member 36 in the upper portion of the casing. Held to the pla-te 36 by means of the screw 35 is a spring linger 37, and extending over the free end of this spring lfinger is a second spring linger 38 held to the member 36 by a screw 39. Pivotally mounted yon the insulated member 36 by vmeans ofthe screw .40 is a metal arm 41,

one end of this arm passing through a slot inside of the casing 30 and engaging with the door frame 11. This arm acts automatically Yas a switch being 4held in normal or vopen position .when in engagement with the -door frame and in closed position when the door is opened.; the other end of the arm 41 lying between two contact points 42 and 43 disposed through the member 36, and is provided with a spring-finger 44 which maintains aconstant resilient engagement with .contact point 42, when the arm is in engagement with the door frame. When the arm 41 moves away from the door frame the inner end of the arm is forced against the contact point 43 by the spring 44, said spring remaining in contact with the point 42,

thereby closing the circuit between the points 42 and 43 through the arml and the spring.

Extending through the front wall of the upper portion of the casing is an insulated sleeve 45, in which is rotatably mounted a turn button 46, the inner end 46 of which is formed of metal and carries the oppositely disposed blocks of insulation 47. This inner member is disposed between the adj acent ends of the fingers 37y and 38 and when the button is turned in one direction the metallic portion will stand in a vertical position and press the fingers away from each other so that they will be held in resilient engagement against the said member. `When the member is turned into a horizontal position, the insulation 47 will be presented toward the lingers so that no current will pass.

Connecting the binding screw 39 withV the contact point 42 at the other end of the member 3G is a wire 48. A wire 49 is connected to the contact point 43 and thence to the contact member 21. F rom the binding screw 39 down through the portion 29 of the casing, where it is connected to the contact member 20, is a wire 50.

It will thus be seen that the wires 48, 49 and 50 are of the "same polarity and after making contact with the flexible strip 22 follow the same course to the alarm inthe knob, and return through the ground at 28 to the other element of the battery at 32 in the casing 30. When the knob is turned in either direction, the member'22 will contact with the members 20 and 21, so that a circuit will be completed through the said contacts, the wires 49 and 50, posts 39 and 42, metal block 46, pole V33 of the battery, pole 32, casing 30, shell of knob, wire 23, and buzzer through its point of attachment with the knob shell at 28. When the knob is released, the contacts 20, 21, and 22, will disengage, thus breaking the circuit. Thus the alarm would only sound when the knob was turned, and the door would remain open Without the occupants knowing it. To provide against this is the special purpose of the arm or lever 4l. This arm engages against the face of the door frame. when the door Yis closed, but when the door is opened, and left in such position, the arm will be moved on its pivot by the spring 44, so that .said spring engages with the contact 42, and the lever with the contact 43. Current will then pass from the battery through the contacts 87 and 38, contact 42, lever 41, contact 43, contact 20, casing of the knob and casing 30, back to the battery by means of the pole 32. Thus the bell will continue ringing, to advise the occupants that the door has been opened and left in such position, which would mean that the person or visitor was stillin the room.

What is claimed is:

1. In a burglar alarm, the combination with a door and knob, of a source of electricity mounted on the door above the knob, an audible alarm mounted in the knob, electrical connections between the source of electricity and the alarm, and a circuit closing means carried by the knob.

`2. In a burglar alarm, the combination with a door, its knob and escutcheon, of a source oi' electricity mounted on the door, a sounding alarm carried by the knob, electrical connections between the source and the alarm, contact members carried by the escutcheon and insulated therefrom and from the knob, and an operating member carried by the knob for engagement with the contact members for closing the circuit and ringing the alarm when the knob is turned in either direction. i

3. In a burglar alarm, the combination with a door, the frame thereof'and the knob, of an alarm carried by the knob, a source of electricity carried by the door and connected with the alarm, means operable by the knob `for completing the circuit to ring the alarm, and an auxiliary circuit closing means carried by the door and normally held in inoperative position by engagement with the door frame.

In testimony whereof I affix my signature in the presence of two witnesses.

JAMES W. SMITH.

Vitnesses:

J oHN F. DREYER, WALTER HERBERT SMITH.

Copies of this patent may be obtained for five cents each, by addressing theA Commissioner of Patents. Washington, D. C. 

